cps-ir: Merge variables based on set-based liveness and graph coloring.

tests/language/catch_liveness_test.dart

Index: tests/language/catch_liveness_test.dart
diff --git a/tests/language/catch_liveness_test.dart b/tests/language/catch_liveness_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..ede8a441b83422d9dc355c1a7bafbf3ea01a0b28
--- /dev/null
+++ b/tests/language/catch_liveness_test.dart
@@ -0,0 +1,27 @@
+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import "package:expect/expect.dart";
+
+@AssumeDynamic @NoInline
+foo() => 1;
+
+@AssumeDynamic @NoInline
+throwException() => throw 'x';
+
+main() {
+	var x = 10;
+	var e2 = null;
+	try {
+		var t = foo();
+		throwException();
+		print(t);
+		x = 3;
+	} catch(e) {
+		Expect.equals(10, x);
+		e2 = e;
+	}
+	Expect.equals(10, x);
+	Expect.equals('x', e2);
+}